FIG. 4 shows a roll diagram of a printing couple, through which a web B to be printed on runs. In the arrangement shown in FIG. 4, the web B is first guided over an inking roll 1′, with which a first rubber blanket cylinder 2′ and a second rubber blanket cylinder 2″ are in contact, and is led farther for postdamping over another inking roll 1, with which a first rubber blanket cylinder 2 and a second rubber blanket cylinder 2″ are likewise in contact. The roll diagram is described based on the example of a printing couple design used for postdamping. A damping agent applicator roll 11 is in contact with the plate cylinder 3, which is in contact with the rubber blanket cylinder. The damping agent applicator roll 11 is in contact with a distributing roller 12, the so-called damping agent distributor. The damping agent transfer roll 13 is in contact with this distributing roller, and the damping agent transfer roll receives the damping agent sprayed on it via a contactless damping system. The damping agent transfer roll 13, the distributing roller 12 and the damping agent applicator roll 11 transfer the damping agent to the plate cylinder 3, as a result of which the desired predamping and postdamping are achieved.
The inking rolls 4 that are in contact with the plate cylinder 3 transfer ink from the first distributing roller 5a that is in contact with them, the first, so-called distributor. The rubber blanket cylinder 6a, which is further in contact with a second ink distributor 5b, is in contact with the ink distributor 5a, and two other rubber blanket cylinders 6b and 6c are in contact with the said second ink distributor 5b. The rubber blanket cylinder 6c is in contact with the ink film roll 7, with which the ink doctor roll 8 and the dipping roll 10 are in contact in the known manner. The ink distributor 5a is inked in the known manner via the rubber blanket cylinders 6a, 6c, the additional ink distributor 5b, the ink film roll 7, via the ink doctor roll 8, on which the ink is metered by means of doctor knives, which are arranged in the doctor knife bar 9, and via the dipping roll 10, which dips into the ink in the ink tray.
An exemplary inking and damping system is shown in the Applicant's DE 40 12 283 A1 (and corresponding U.S. Pat. No. 5,090,314). DE 40 12 283 A1 and U.S. Pat. No. 5,090,314 are hereby incorporated by reference in their entirety and in particular, the teaching of these documents concerning the design of an inking and damping system is incorporated by reference.
It is known from DE 40 122 83 A1 that distributing rollers have a surface made of copper in order for these rollers to have an ink-friendly surface.
If two different inks are printed on two webs located next to each other, it may happen that the damping agent distributors 12 moving to and fro by an oscillator 14 mix the different inks used in two webs running next to each other, which leads to unsatisfactory printing results.